Contrast modulation and attentional modulation in the LGN and SC. Distributions of the CMI (A, B) and AMI (D–G) are shown for all voxels in all subjects in the LGN (A–C) and SC (D–F). In A and B, voxels with CMI < 0.25 are shaded in gray. These same voxels appear shaded in the AMI distributions. In B and E, the AMI is shown for the dot motion stimulus in the LGN and SC, respectively. In C and F, the AMI is shown for the color and shape stimulus in the LGN and SC.